Coal Bed Methane Reservoir in the Mengjin Coalfield, Henan Province, China

Abstract

Coal is a continuous unconventional gas reservoir and coal bed methane has the potential to make an important contribution to the future energy demands. The second member coal seam of Shaxi Formation in the Mengjin coalfield is one of the most important methane bearing and exploration formations. Based on industrial analysis, elemental analysis and methane content test of thirty-five coal samples from the Mengjin coalfield, together with other geological data of the past five-year exploration, the factors that controlling the coal bed methane reservoir are identified in the Mengjin coalfield. The thick-bedded No. 2 coal seam, about 6 meters, of the Shaxi formation are continuous distributed in the Mengjin coalfield. The burial depth is from 400 to 800 meters, this is suitable for coal bed methane exploit. There is a trend which an increase in the degree of coalification is correlated with rise content of methane in No. 2 coal. Coal rank has a significant effect on the content of coal bed methane. The relationships between methane content and basin hydrodynamics are also described and discussed in this paper. The deep stagnant zone contains the largest coal bed methane accumulation. Future geological exploration for coal bed methane in Mengjin coalfield should be guided by the essential factors identified in this study. The application of them could benefit to solving the discrepancy between the amount of reserves and the question of their exploitability.